Downhole layered gas injection tubular column

Abstract

The utility model discloses an underground separate layer gas injection tubular column which comprises a casing pipe and an oil pipe, the oil pipe is arranged on the inner side of the casing pipe, the oil pipe is provided with a plurality of packers from top to bottom, the oil pipe is provided with an injection allocation assembly along the position below each packer, and the injection allocation assemblies are aligned with a gas injection layer. Gas injection ports are formed in the positions, aligned with the gas injection layer, of the sleeve, and the injection allocation assembly is used for injecting gas into the gas injection layer and reducing the pressure of the gas; a screwed plug is arranged at the bottom end of the oil pipe. The injection allocation assembly comprises an injection allocation device, multiple air taps and a fixed connector, the multiple air taps are arranged in a stacked mode, carbon dioxide generates energy loss through multiple hole shrinkage processes, and therefore the single-layer carbon dioxide injection pressure is reduced; meanwhile, the gas nozzles are longitudinally stacked, so that gas enters from the top end of the injection allocation device and flows out from the side face of the injection allocation device after being decompressed through the gas nozzles, and the purpose of injecting gas into a gas injection layer is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of oil production, in particular to a downhole stratified gas injection pipe string. Background Art

[0002] With the continuous development of oil extraction technology, methods for improving oil recovery are also constantly innovating. Supercritical CO2 flooding technology, as an effective method to improve oil recovery, has received widespread attention in recent years. In the process of supercritical CO2 flooding, downhole stratified gas injection is a key technology. At present, in downhole gas injection operations, there are some significant problems with the commonly used gas injection strings. For example, the stratification effect of traditional gas injection strings is not ideal, and it is difficult to achieve precise gas injection control in different layers, which leads to uneven distribution of gas injection, affects the oil recovery effect, and reduces the oil recovery rate. Moreover, since it is impossible to accurately inject supercritical CO2 into the predetermined formation layer, it may cause excessive gas injection in some layers, while insufficient gas injection in other layers, which not only wastes resources, but also may cause a series of geological problems.

[0003] In the prior art, the Chinese invention patent with patent number CN201510255717.5 discloses a supercritical CO2 downhole stratified gas injection string and operation method, which is used for CO2 downhole stratified gas injection; the oil pipe is installed in the casing, the top packer, the interlayer packer, the adjustable gas distributor and the blind plug are connected by the oil pipe, an adjustable gas distributor is installed for each oil layer, the measuring and adjusting instrument is located in the adjustable gas distributor and can be moved between the adjustable gas distributors; the gas distribution hole of the adjustable gas distributor is provided with a one-way valve mechanism; the part above the gas distribution hole is provided with an inner light pipe section, and the measuring and adjusting instrument includes an extrusion sealing section, and the rubber cylinder on the extrusion sealing section is sealed with the inner light pipe section. The operation method is: after the well is completed, the gas distribution hole is opened with a cable belt measuring and adjusting instrument for gas injection, and then the measuring and adjusting instrument is positioned at the adjustable gas distributor, and the gas distribution amount of each level is measured and adjusted through the ground control instrument. Since a sliding sleeve is installed above the top packer, the problem of penetration and retention of annular anti-corrosion protection fluid is solved; since an extrusion sealing section is set on the measuring and adjusting instrument, the problem of difficulty in small flow testing is solved.

[0004] The technical solution provided by the above patent is to adjust the gas distribution volume through the measuring and adjusting instrument, and the gas injection layer needs to be exhausted by the distributor, and when injecting gas into the gas injection layer, it is necessary to ensure that the gas pressure of the gas ejected is within a certain range. Excessive gas pressure can easily cause abnormalities in the gas injection layer. The existing distributor's gas nozzle cannot reduce the gas pressure, which is not conducive to the safe and stable gas supply to the gas injection layer. Utility Model Content

[0005] The utility model aims to provide a downhole layered gas injection string, aiming to improve the problem that the gas nozzle of the existing dispenser proposed in the above background technology cannot reduce the pressure of the gas, which is not conducive to safe and stable gas supply to the gas injection layer.

[0006] The utility model is achieved in this way:

[0007] A downhole layered gas injection string includes a casing and an oil pipe. The oil pipe is arranged on the inner side of the casing and is provided with a plurality of packers from top to bottom. The oil pipe is installed with an injection assembly along the position below each packer. The injection assembly is aligned with the gas injection layer. The casing is aligned with the gas injection layer and is provided with a gas injection port. The injection assembly is used to inject gas into the gas injection layer and reduce the pressure of the gas. A thread plug is provided at the bottom of the oil pipe.

[0008] Preferably, the injection assembly includes an injector, an air nozzle and a fixed joint. A plurality of groups of air nozzles are provided on the inner side of the injector. A plurality of air nozzles are provided in each group from top to bottom, and adjacent air nozzles are connected to each other. The position of the air inlet at the top of each group of air nozzles is connected to the inner cavity of the injector; the air inlet of each group of air nozzles is connected to a fixed joint, and the fixed joint is pressed against the inner side of the injector.

[0009] Preferably, the inner and outer sides of the dispenser are hollow, and the air nozzle is arranged inside the hollow cavity; the outer side of the dispenser is provided with a plurality of air outlet holes; the top and bottom ends of the dispenser are provided with adapter rings, and the inner top end of the dispenser is provided with a plurality of mounting holes, and the mounting holes are used to install the air nozzle.

[0010] Preferably, adjacent gas nozzles are connected via connecting pipes, and a bend is provided at the top of each group of gas nozzles, and the end of the bend that is not connected to the gas nozzle protrudes from the mounting hole.

[0011] Preferably, an air inlet hole is provided at one end of the air nozzle, and an exhaust hole is provided at the other end, the diameter of the air inlet hole is smaller than the diameter of the exhaust hole; and the axis of the air inlet hole and the axis of the air nozzle are not in the same straight line.

[0012] Preferably, a fixing ring is provided at one end of the fixing joint facing the bent pipe, and the fixing ring is connected to the inner thread of the bent pipe; a connecting groove is provided at the other end of the fixing joint.

[0013] Compared with the prior art, the beneficial effects of the utility model are:

[0014] 1. The injection assembly of the utility model includes an injector, a gas nozzle and a fixed joint. A plurality of gas nozzles are provided, and the plurality of gas nozzles are stacked. The carbon dioxide produces energy loss through multiple shrinking processes, thereby reducing the injection pressure of a single layer of carbon dioxide. At the same time, the gas nozzles are stacked longitudinally, so that the gas enters from the top of the injector and flows out from the side of the injector after being decompressed by the gas nozzles, thereby achieving the purpose of injecting gas into the gas injection layer.

[0015] 2. The fixed joint of the utility model is convenient for fixing the position of the gas inlet of the gas nozzle on the inner side of the dispenser, ensuring that the gas can smoothly enter the inside of the gas nozzle, which is convenient for the use of the entire gas injection string. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0017] Figure 2 It is a structural schematic diagram of the injection assembly of the utility model;

[0018] Figure 3 It is a structural schematic diagram of the utility model dispenser;

[0019] Figure 4 It is a structural schematic diagram of the gas nozzle of the utility model;

[0020] Figure 5 This is a cross-sectional view of the gas nozzle of the utility model;

[0021] Figure 6 It is a structural schematic diagram of the fixed joint of the utility model.

[0022] In the figure: 1. casing; 2. oil pipe; 3. packer; 4. injection assembly; 41. injector; 411. air outlet; 412. adapter ring; 413. mounting hole; 42. air nozzle; 421. connecting pipe; 422. elbow; 423. air inlet; 424. exhaust hole; 43. fixing joint; 431. fixing ring; 432. connecting groove; 5. air injection port; 6. air injection layer; 7. screw plug. DETAILED DESCRIPTION

[0023] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] The following is a further description with reference to the accompanying drawings and specific embodiments:

[0025] Example 1

[0026] like Figure 1As shown, a downhole layered gas injection string includes a casing 1 and an oil pipe 2. The oil pipe 2 is arranged inside the casing 1. The oil pipe 2 is convenient for cooperating with oil production equipment to carry out various oil production operations, and is also convenient for cooperating with other components to inject gas into the gas injection layer 6. The oil pipe 2 is provided with multiple packers 3 from top to bottom. The packers 3 are convenient for separating different layers and injecting gas into each layer. The oil pipe 2 is equipped with an injection assembly 4 along the position below each packer 3. The injection assembly 4 is aligned with the gas injection layer 6. The casing 1 is aligned with the gas injection layer 6. The gas injection port 5 is convenient for the gas flowing out of the injection assembly 4 to be discharged smoothly into the gas injection layer 6. The injection assembly 4 is used to inject gas into the gas injection layer 6 and reduce the pressure of the gas; the bottom end of the oil pipe 2 is provided with a screw plug 7, and the screw plug 7 is used to plug the bottom end opening of the oil pipe 2.

[0027] Working principle: When in use, the injection assembly 4 is connected to the oil pipe 2 according to the use requirements, and the packer 3 is installed at the corresponding position of the oil pipe 2, and the different layers are separated by the packer 3; then the gas supply equipment can be used to inject gas into the gas injection layer 6. After the gas enters from the gas distribution assembly, it is decompressed inside the gas distribution assembly, so that the pressure of the gas ejected from the gas distribution assembly is greatly reduced, thereby avoiding the problem of instability of the gas injection layer 6 caused by excessive pressure of the jet gas. Compared with the prior art, the injection assembly 4 of the present application includes an injector 41, a gas nozzle 42 and a fixed joint 43. There are multiple gas nozzles 42, and the multiple gas nozzles 42 are stacked. Through multiple reduction processes, the carbon dioxide produces energy loss, thereby reducing the injection pressure of a single layer of carbon dioxide; at the same time, the gas nozzles 42 are stacked longitudinally, so that the gas enters from the top of the injector 41, and flows out from the side of the injector 41 after being decompressed by the gas nozzle 42, thereby achieving the purpose of injecting gas into the gas injection layer 6.

[0028] Example 2

[0029] like Figure 1 As shown, a downhole layered gas injection string includes a casing 1 and an oil pipe 2. The oil pipe 2 is arranged inside the casing 1. The oil pipe 2 is convenient for cooperating with oil production equipment to carry out various oil production operations, and is also convenient for cooperating with other components to inject gas into the gas injection layer 6. The oil pipe 2 is provided with multiple packers 3 from top to bottom. The packers 3 are convenient for separating different layers and injecting gas into each layer. The oil pipe 2 is equipped with an injection assembly 4 along the position below each packer 3. The injection assembly 4 is aligned with the gas injection layer 6. The casing 1 is aligned with the gas injection layer 6. The gas injection port 5 is convenient for the gas flowing out of the injection assembly 4 to be discharged smoothly into the gas injection layer 6. The injection assembly 4 is used to inject gas into the gas injection layer 6 and reduce the pressure of the gas; the bottom end of the oil pipe 2 is provided with a screw plug 7, and the screw plug 7 is used to plug the bottom end opening of the oil pipe 2.

[0030] like Figure 2As shown, the injection assembly 4 includes an injector 41, a gas nozzle 42 and a fixed joint 43. A plurality of groups of gas nozzles 42 are arranged on the inner side of the injector 41. Each group of gas nozzles 42 is arranged in sequence from top to bottom, and adjacent gas nozzles 42 are connected to each other. The position of the top air inlet of each group of gas nozzles 42 is connected to the inner cavity of the injector 41; the air inlet of each group of gas nozzles 42 is connected to the fixed joint 43, and the fixed joint 43 is pressed tightly against the inner side of the injector 41; this structure is convenient for the injector 41 to cooperate with the gas nozzle 42 to reduce the pressure of the gas to be injected into the gas injection layer 6; and a multi-stage gas nozzle 42 series structure is adopted for throttling pressure difference control, and the carbon dioxide is caused to produce energy loss through multiple shrinking processes, thereby reducing the injection pressure of a single layer of carbon dioxide.

[0031] like Figure 3 and Figure 4 As shown, the inner and outer sides of the dispenser 41 are hollow, and the gas nozzle 42 is arranged inside the hollow cavity; it is convenient for the gas nozzle 42 to be used stably with the dispenser 41. The outer side of the dispenser 41 is provided with a plurality of gas outlet holes 411; the gas outlet holes 411 are convenient for the gas flowing out of the gas nozzle 42 to be smoothly discharged into the gas injection layer 6 through the gas outlet holes 411. The top and bottom ends of the dispenser 41 are both provided with adapter rings 412, which are convenient for the dispenser 41 to be connected to the oil pipe 2, and convenient for the installation and use of the dispenser 41. The top inner side of the dispenser 41 is provided with a plurality of mounting holes 413, and the mounting holes 413 are used to install the gas nozzle 42.

[0032] like Figure 4 and Figure 5 As shown, adjacent gas nozzles 42 are connected by connecting pipes 421. This structure can ensure that adjacent gas nozzles 42 are connected. A bend pipe 422 is provided at the top of each group of gas nozzles 42. The end of the bend pipe 422 that is not connected to the gas nozzle 42 protrudes from the mounting hole 413. The bend pipe 422 can guide the gas to facilitate the gas nozzle 42 to smoothly enter the inner side of the dispenser 41. An air inlet hole 423 is provided at one end of the gas nozzle 42, and an exhaust hole 424 is provided at the other end. The diameter of the air inlet hole 423 is smaller than the diameter of the exhaust hole 424; and the axis of the air inlet hole 423 is not in the same straight line as the axis of the gas nozzle 42. The gas nozzle 42 of this structure causes energy loss of carbon dioxide through multiple diameter reduction processes, thereby ensuring that the pressure of the gas injected into the gas injection layer 6 is effectively reduced.

[0033] like Figure 6 As shown, a fixing ring 431 is provided at one end of the fixing joint 43 facing the elbow 422, and the fixing ring 431 is connected to the inner thread of the elbow 422; it is convenient to stably connect the elbow 422 to the fixing joint 43 through the fixing joint 43. A connecting groove 432 is provided at the other end of the fixing joint 43, and the connecting groove 432 is convenient for connecting the fixing joint 43 to an external pipeline.

[0034] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be modified and varied in various ways. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A downhole stratified gas injection string, comprising a casing (1) and an oil pipe (2), characterized in that: The oil pipe (2) is arranged inside the casing (1), and the oil pipe (2) is provided with a plurality of packers (3) from top to bottom. The oil pipe (2) is provided with an injection assembly (4) at a position below each packer (3). The injection assembly (4) is arranged aligned with the gas injection layer (6). The casing (1) is provided with a gas injection port (5) at a position aligned with the gas injection layer (6). The injection assembly (4) is used to inject gas into the gas injection layer (6) and reduce the pressure of the gas. A threaded plug (7) is provided at the bottom end of the oil pipe (2).

2. A downhole stratified gas injection string according to claim 1, characterized in that: The dispensing assembly (4) comprises an injector (41), an air nozzle (42) and a fixed joint (43). A plurality of groups of air nozzles (42) are arranged on the inner side of the injector (41). Each group of air nozzles (42) is provided with a plurality of air nozzles (42) in sequence from top to bottom, and adjacent air nozzles (42) are connected to each other. The position of the air inlet at the top of each group of air nozzles (42) is connected to the inner cavity of the injector (41); the air inlet of each group of air nozzles (42) is connected to the fixed joint (43), and the fixed joint (43) is pressed tightly against the inner side of the injector (41).

3. A downhole stratified gas injection string according to claim 2, characterized in that: The inner and outer sides of the dispenser (41) are hollow, and the air nozzle (42) is arranged inside the hollow cavity; the outer side of the dispenser (41) is provided with a plurality of air outlet holes (411); the top and bottom ends of the dispenser (41) are both provided with adapter rings (412), and the inner top end of the dispenser (41) is provided with a plurality of mounting holes (413), and the mounting holes (413) are used to mount the air nozzle (42).

4. A downhole stratified gas injection string according to claim 3, characterized in that: Adjacent gas nozzles (42) are connected via connecting pipes (421), and a bent pipe (422) is provided at the top of each group of gas nozzles (42), and the end of the bent pipe (422) not connected to the gas nozzle (42) protrudes from the mounting hole (413).

5. A downhole stratified gas injection string according to claim 4, characterized in that: The air nozzle (42) is provided with an air inlet hole (423) at one end and an air outlet hole (424) at the other end; the diameter of the air inlet hole (423) is smaller than the diameter of the air outlet hole (424); and the axis of the air inlet hole (423) and the axis of the air nozzle (42) are not on the same straight line.

6. A downhole stratified gas injection string according to claim 4, characterized in that: A fixing ring (431) is provided at one end of the fixing joint (43) facing the bent pipe (422), and the fixing ring (431) is threadedly connected to the inner side of the bent pipe (422); a connecting groove (432) is provided at the other end of the fixing joint (43).

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